Pigment Paste Viscosity Control via Alkoxylated Compounds
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Solution Overview
Problem
Existing water- and solvent-based pigment pastes face challenges with high viscosity, leading to dosing difficulties and storage issues, while attempts to avoid solvents result in germ contamination or the need for biocides, which are environmentally undesirable.
Innovation Solution
The use of alkoxylated compounds, such as alkoxylated carboxylic acids, alkoxylated alcohols, and poloxamers, along with dispersants, to create water-free and solvent-free pigment pastes with reduced viscosity, making them flowable and pumpable, while meeting environmental standards by avoiding biocides and solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If highly concentrated pigment pastes are used to reduce storage space, then the amount of paste on mixing machines is reduced, but the viscosity increases making dosing difficult or impossible
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific low-viscosity solvents (glycols, esters, ethers) and controlling solvent-to-pigment ratios. This allows highly concentrated pastes to maintain low viscosity by adjusting the solvent type and amount, enabling both compact storage and easy dosing through parameter optimization rather than structural changes
Solution Approach 2:
The patent uses solvent substances as intermediaries between the pigment particles and the dosing system. These solvents mediate by reducing interparticle friction and enabling flow, allowing the highly concentrated paste to be pumped and dosed efficiently without changing the fundamental high-concentration formulation
2Reliability
If water is eliminated as a solvent to prevent microbial contamination, then germ growth is prevented, but the paste requires biocides which are environmentally undesirable
Solution Approach 1:
The patent extracts water completely from the solvent system and replaces it with organic solvents (glycols, esters, ethers). This removal of water eliminates the medium required for microbial growth, while the resulting anhydrous organic system inherently resists microbial contamination without requiring biocidal additives
Solution Approach 2:
The patent employs a solvent system based on relatively short-lived organic compounds (glycols, esters, ethers) that can be easily replaced or degraded. These solvents provide temporary protection against microbial growth during the product's service life, after which they decompose harmlessly, eliminating the need for persistent biocides
3Volume of moving object
If the amount of solvent is decreased to reduce storage space, then space requirements are reduced, but the viscosity increases making the paste harder to dose
Solution Approach 1:
The patent changes the physical parameters of the solvent phase by selecting specific low-viscosity compounds (glycols with 2-12 carbon atoms, esters, ethers) and controlling their quantity and molecular weight. This allows the system to maintain low viscosity even at high pigment concentrations by optimizing solvent chain length, branching, and intermolecular interaction parameters
Solution Approach 2:
The patent creates a composite solvent system combining multiple components (glycols, esters, ethers) with complementary properties. This composite approach allows tuning of both viscosity and solvating power, achieving a balance where sufficient solvent is present to maintain flowability while keeping the overall paste concentration high for compact storage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resulting paste compositions have viscosities suitable for easy pumping, are environmentally compliant, and meet the 'Blue Angel' criteria, allowing for efficient use in tinting products without the need for solvents or biocides.
Implementation Method 1
alkoxylated compounds, specifically certain polyglycols including EO-PO block copolymers, as well as alkoxylated carboxylic acids, especially oleic acid alkoxylates, allow the production of free-flowing and pumpable pigment and filler pastes
Implementation Method 2
Free-flowing and pumpable in this context means that the pastes exhibit a viscosity (plate/plate, 20 °C) of less than 1,000 mPas at a shear rate of 500 1/s and less than 20,000 mPas at 1 1/s. The pastes are considered anhydrous, containing at most up to 2 wt% water, which is introduced via the pigments or, if applicable, the residual moisture of the alkoxylates and/or dispersants
Data Source
AI summary
Proposed are paste compositions containing and/or consisting of (a) at least one colour pigment and/or a filler, (b) at least one alkoxylated compound, in particular an alkoxylated carboxylic acid and/or an alkoxylated alcohol and/or a poloxamer, and optionally (c) at least one dispersant.